Edgard (João Miguel) works as a subordinate in the company of millionaire Werneck (Gracindo Junior) and is in love with Ritinha (Leandra Leal), a simple woman who works as a teacher to support her mother and her three sisters. One day, Peixoto (Leon Góes), Werneck's son-in-law, makes him a proposal to marry Maria (Leticia Colin), the boss's daughter. The reason is that Maria was abused and now is being forced to marry by her family. Edgard hesitates first but accepts the offer. From then on he enters into a great doubt: should he deposit the check and marry Maria or stay with Ritinha, his great love?

Rat Fever is the alcohol-drenched story of an unrequited love. The poet Zizo, a pure-bred anarchist, is lost as soon as he meets the sober Eneida. She doesn't mind being his muse, but she won't go any further than that - whereas in Zizo's circle of friends, made up of social losers, Bohemians and other proud outsiders, everyone goes to bed with everyone else. Meanwhile, Zizo is busy with his dubious battle against 'the system', using his self-published newsletter 'Febre do rato' and a series of subversive street performances that primarily seem to reach his own friends.